Systems and methods for ink-based digital printing

Abstract

An ink-based digital printing system for variable data lithographic printing includes an imaging member and a dampening fluid/carrier patterning system. An inkjet-type device of the patterning system jets material onto an imaging member. The as-jetted material includes dampening fluid and carrier component such as a wax jetted in a single phase. Upon contact with a surface of an imaging member, the jetted material cools and phase separation occurs, the dampening fluid leaching to a surface of the solid component on the imaging member surface, dampening the solid component, which forms an image according to image data input to the patterning system.

What is claimed is: 
     
       1. An ink-based digital printing system useful for ink printing, comprising:
 an imaging member having a surface at a surface temperature; 
 a dampening fluid patterning system comprising an inkjet configured to form a latent image by jetting droplets on the surface of the imaging member, wherein each jetting droplet comprises dampening fluid and carrier in a single fluid phase at a jetting temperature, wherein at the imaging member each jetting droplet spreads and holds a spot size of less than 50 micrometers, and wherein the jetting temperature is higher than the surface temperature; 
 wherein the carrier solidifies upon contacting the imaging member and reaching a temperature lower than the jetting temperature; 
 wherein upon contact with the surface of the imaging member the jetted droplet will phase separate into a solid component and a liquid dampening fluid component that migrates to a surface of the solid component enabling formation of a dampening fluid layer; 
 a transfer member, the transfer member being configured to receive a dampening fluid pattern from the surface of the imaging member, the transfer member and the imaging member being arranged to define a dampening fluid image loading nip for contact transfer, the dampening fluid being separate from and immiscible with solid carrier on the imaging member surface; and 
 an inker system, the inker system being configured to apply ink onto the transfer member having the transferred dampening fluid layer pattern to form an ink image based on the dampening fluid pattern. 
 
     
     
       2. The system of  claim 1 , wherein the dampening fluid is selected to be liquid at room temperature. 
     
     
       3. The system of  claim 1 , wherein the jetted dampening fluid forming a high resolution image on the surface of the imaging member and wherein the dampening fluid layer is about 0.1 micrometers to 1.0 micrometer thick. 
     
     
       4. The system of  claim 1 , the dampening fluid comprising fountain solution. 
     
     
       5. The system of  claim 4 , comprising:
 an imaging member cleaning system, the imaging member cleaning system including a heating system and a doctor blade. 
 
     
     
       6. The system of  claim 1 , the carrier comprising paraffin. 
     
     
       7. The system of  claim 1 , the dampening fluid and the carrier being miscible and in a same phase at a temperature of the dampening fluid and carrier as jetted from the patterning system. 
     
     
       8. The system of  claim 1 , the dampening fluid comprising a silicone fluid. 
     
     
       9. The system of  claim 1 , wherein the dampening fluid and the carrier are miscible and in a same phase at a temperature of the dampening fluid and carrier as jetted from the patterning system, and
 the dampening fluid is selected to be liquid at room temperature. 
 
     
     
       10. A method for ink-based digital printing, comprising:
 forming a dampening fluid pattern on a surface of an imaging member by jetting material in a single phase, the material comprising dampening fluid and carrier in a single fluid phase at a jetting temperature and wherein a droplet of the jetting material when at the imaging member fractions into a solid component and a liquid dampening fluid component that migrates to a surface of the solid component enabling formation of a dampening fluid layer with a spot size of less than 50 micrometers; 
 wherein the carrier solidifies upon contacting the imaging member and reaching a temperature lower than the jetting temperature; 
 transferring the dampening fluid pattern to a transfer member at a dampening fluid pattern loading nip defined by the transfer member and the imaging member; and 
 inking a surface of the transfer member having the dampening fluid pattern to produce an ink pattern according to the dampening fluid pattern. 
 
     
     
       11. The method of  claim 10 , comprising:
 transferring the ink pattern to a substrate at an ink pattern transfer nip formed by the transfer member and a substrate transport system. 
 
     
     
       12. The method of  claim 11 , wherein the dampening fluid is selected to be liquid at room temperature. 
     
     
       13. The method of  claim 10 , wherein the dampening fluid and solid carrier are configured whereby the dampening fluid and carrier are miscible at a jetting temperature and are jetted in a single phase, and wherein the dampening fluid and carrier phase separate upon contacting the imaging member, the carrier being deposited in a pattern according to image data, and the dampening fluid leaching to a surface of and dampening the carrier to form the dampening fluid pattern. 
     
     
       14. The method of  claim 10 , comprising:
 transferring the ink pattern to a substrate at an ink pattern transfer nip formed by the transfer member and a substrate transport system, 
 wherein the dampening fluid and solid carrier are configured whereby the dampening fluid and carrier are miscible at a jetting temperature and are jetted in a single phase, and wherein the dampening fluid and carrier phase separate upon contacting the imaging member, the carrier being deposited in a pattern according to image data, and the dampening fluid leaching to a surface of and dampening the carrier to form the dampening fluid pattern, and 
 the dampening fluid is selected to be liquid at room temperature.